Method and apparatus for providing secure control of software or firmware code downloading and secure operation of a computing device receiving downloaded code

Abstract From the Canadian patent

A method and system for secure downloading of software includes a master processor for receiving downloaded blocks of code which are associated with a computed authentication signature derived from the content of the code block. A secure processor re-computes the authentication signature fromt he content of the downloaded code block and compares the computed signature to that received with the code block. If the signatures do not match or if no signature is appended to the downloaded data the secure processor determines , that the code is from an authorized sender or has been altered during transmission, perhaps to include a virus. The secure processor then takes appropriate …